Washing machine

ABSTRACT

In a washing machine of the present disclosure, a drive shaft rotating a pulsator and a dehydration shaft rotating a washing tub are connected to each other or disconnected from each other while a clutch operated by a solenoid is lifted, a current is intermittently applied to the solenoid while the clutch is lowered, and thus, a lowering speed of the clutch can be reduced.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean PatentApplication No. 10-2019-0005468, filed in the Republic of Korea on, Jan.16, 2019, the disclosure of which is incorporated herein by reference inits entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present disclosure relates to a washing machine including a clutchsystem for connecting or disconnecting a drive shaft and a dehydrationshaft.

Related Art

A washing machine including a clutch which is operated by a solenoid andselectively connects (or shaft coupling) or disconnects (or shaftdecoupling) a washing shaft and a dehydration shaft is well known. Forexample, Korean Patent Laid-Open Publication No. 2003-0023316(hereinafter, referred to as a “related art”) discloses a structure inwhich a slider serration-coupled to a dehydration shaft is separatedfrom a driving portion formed in a rotor of a washing motor while beinglifted by a suction force of a solenoid.

Meanwhile, in the related art, there is a problem that a current iscontinuously applied to the solenoid in order to maintain a state wherethe slider and the rotor are separated from each other.

SUMMARY OF THE INVENTION

The present disclosure provides a washing machine in which a clutchingcoupler operated by a suction force of a solenoid connects a drive shaftrotating a pulsator and a dehydration shaft rotating a washing tub toeach other a lowered position and disconnect the drive shaft and thedehydration shaft at a lifted position lifted from the lowered positionand the clutching coupler is prevented from being lowered at anexcessive high speed while being lowered to connect the drive shaft andthe dehydration shaft to each other.

The present disclosure also provides a washing machine capable ofreducing a noise generated in a process in which the drive shaft and thedehydration shaft is connected to each other.

The present disclosure relates to a washing machine in which a driveshaft rotating a pulsator and a dehydration shaft rotating a washingtube are connected to each other or disconnected from each other by aclutch operated by a solenoid.

The washing machine includes a magnetic core configured to surround aperiphery of the solenoid, an armature configured to be lifted by anattraction force between the armature and the magnetic core when acurrent is applied to the solenoid, and a clutching coupler configuredto move integrally with the armature and to be lifted or lowered alongthe dehydration shaft.

The clutching coupler shaft-couples the drive shaft and the dehydrationshaft to each other at a lowered position and shaft-decouples the driveshaft and the dehydration shaft from each other at a lifted positionlifted from the lowered position according to the lifting of thearmature. An elastic member configured to press the clutching couplerdownward is provided.

A lever configured to have a support point of which a position is fixedwith respect to the dehydration shaft and an operation end located at apoint spaced by a predetermined distance from the support point isprovided, and a guide groove configured to guide a relative movement ofthe operating end with respect to the clutching coupler when theclutching coupler is lifted or lowered is provided on an innerperipheral surface of the clutching coupler.

A lowering restriction section is disposed in the guide groove. When theclutching coupler is located at the lifted position, the operating endis caught by the lowering restriction section. Accordingly, theclutching coupler is not lowered and a position thereof can bemaintained even when a current is not applied to the solenoid.

The guide groove includes a lowering guide section which guides theoperating end located in the locking groove to an operating end loweredpoint located below the locking groove when the clutching coupler islifted and a lifting guide section which guides the operating endlocated at the operating end lowered point to an operating end liftedpoint located above the lowering restriction section when the clutchingcoupler is lowered.

A controller for controlling the current applied to the solenoid isprovided, and the controller cuts off the current applied to thesolenoid in a state where the operating end is located at the operatingend lowered point so that the operating end is guided along the liftingguide section and repeats application and interruption of the current tothe solenoid until the operating end reaches the operating end liftedpoint.

A predetermined point of the lever between the support point and theoperating end may be pressed by an upper end of the elastic member andthe operating end may press a bottom of the guide groove by a momentgenerated based on the support point.

The dehydration shaft may include a tubular insertion hole extendinghorizontally, and the lever may include a vertical portion configured toextend vertically, a support portion configured to be bent at an upperend of the vertical portion to extend horizontally in a first directionand to be inserted into the insertion hole, and an operation portionconfigured to extend horizontally in a second direction opposite to thefirst direction at a lower end of the vertical position to constitutethe operating end.

The elastic member may be disposed below the support portion, and anupper end of the elastic member may press the support portion upward.

After the controller applies the current to the solenoid for a firsttime, the controller may cut off the current for a second time, andthereafter, apply the current again for a third time shorter than thefirst time.

After the controller repeatedly cuts off the current for the second timeand applies the current for the third time, the controller may cut offthe current for a fourth time, and thereafter, apply the current for afifth time longer than the third time. The fifth time may be shorterthan the first time.

The lowering restriction section may include a locking groove configuredto be formed to be open downward such that the operating end is insertedfrom below, and the washing machine may further include a separationguide section configured to be located in the guide groove, to come intocontact with the operating end when the current is applied to thesolenoid in a state where the operating end is located in the lockinggroove, and to guide turning of the operating end about the supportpoint such that the operating end is separated from the locking groove.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal sectional view illustrating a washing machineaccording to an embodiment of the present disclosure.

FIG. 2 is an exploded perspective view illustrating a portion of thewashing machine according to the embodiment of the present disclosure.

FIG. 3A is a perspective view of a clutch illustrated in FIG. 2.

FIG. 3B is a side view thereof.

FIG. 3C is a plan view thereof.

FIG. 4A is a perspective view of a rotor hub illustrated in FIG. 2.

FIG. 4B is a plan view thereof.

FIG. 5A is a view illustrating a state where the clutch is located at aconnection position.

FIG. 5B is a view illustrating a state where the clutch is lifted fromthe connection position and is separated from the rotor hub.

FIG. 6 is a view illustrating a guide groove and a lever.

FIG. 7 is a view illustrating the guide groove.

FIG. 8A is a graph illustrating a current applied to a solenoid in aprocess in which a clutching coupler is lowered to connect a drive shaftand a dehydration shaft to each other.

FIG. 8B is a graph illustrating a speed with respect to a lowereddistance of the clutch coupler.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 1 is a longitudinal sectional view illustrating a washing machineaccording to an embodiment of the present disclosure. FIG. 2 is anexploded perspective view illustrating a portion of the washing machineaccording to the embodiment of the present disclosure. FIG. 3A is aperspective view of a clutch illustrated in FIG. 2, FIG. 3B is a sideview thereof, and FIG. 3C is a plan view thereof. FIG. 4A is aperspective view of a rotor hub illustrated in FIG. 2 and FIG. 4B is aplan view thereof. FIG. 5A is a view illustrating a state where theclutch is located at a connection position and FIG. 5B is a viewillustrating a state where the clutch is lifted from the connectionposition and is separated from the rotor hub. FIG. 6 is a viewillustrating a guide groove and a lever. FIG. 7 is a view illustratingthe guide groove. FIG. 8A is a graph illustrating a current applied to asolenoid in a process in which a clutching coupler is lowered to connecta drive shaft and a dehydration shaft to each other and FIG. 8B is agraph illustrating a speed with respect to a lowered distance of theclutch coupler.

Hereinafter, the washing machine according to the embodiment of thepresent disclosure will be described with reference to FIGS. 1 to 8B.

Referring to FIG. 1, a casing 1 forms an outline of the washing machine,and a space in which a reservoir 3 is accommodated is formed inside thecasing 1. The casing 1 may include a cabinet 11 which has an open uppersurface, and a top cover 12 which is coupled to the open upper surfaceof the cabinet 11 and has an inlet through which laundry is introducedin a central portion thereof. A door (not illustrated) for opening orclosing the inlet is rotatably coupled to the top cover 12. The topcover 12 may include a control panel 14. The control panel 14 mayinclude an input unit (for example, a button, a dial, a touch pad, orthe like) which receives various control commands for controlling anoperation of the washing machine from a user, and a display unit (forexample, LCD display, LED display, or the like) for visually displayingan operation state of the washing machine.

A water supply pipe 7 for guiding water supplied from an external watersource such as a faucet and a water supply valve 8 for regulating thewater supply pipe 7 may be provided. The water supply valve 8 may becontrolled by the controller 17. The controller 17 may control theoverall operation of the washing machine as well as the water supplyvalve 8. The controller 17 may include a microprocessor having a memoryfor storing data. Hereinafter, unless otherwise mentioned, it will beunderstood that controls of electrical/electronic componentsconstituting the washing machine are performed by the controller 17.

A drawer 18 containing a detergent may be accommodated in the top cover12 to be withdrawn. Water supplied through the water supply valve 8 ismixed with the detergent while passing through the drawer 18, andthereafter, is discharged into a reservoir 3 or the washing tub 4.

A discharge pipe 21 through which the water is discharged from thereservoir 3 and a drain valve 22 which controls the discharge pipe 21may be provided. The water discharged through the discharge pipe 21 maybe pumped by a drain pump 24 and discharged to the outside of thewashing machine through a drain pipe 25.

The washing tub 4 accommodates the laundry and is rotated about avertical axis in the reservoir 3. A pulsator 5 is rotatably provided inthe washing tub 4. The pulsator 5 is connected to a drive shaft 6 a. Aplurality of holes may be formed in the washing tub 4 so that the watermay flow between the reservoir 3 and the washing tub 4.

The drive shaft 6 a rotates the pulsator 5, and thus, is rotated by amotor 6. The drive shaft 6 a is connected to a rotor 63 of the motor 6.The drive shaft 6 a may be directly connected to the pulsator 5 (thatis, a rotation ratio of the drive shaft and the pulsator is 1:1).However, the present disclosure is not limited thereto, and may furtherinclude planetary gear trains which convert an output of the drive shaft6 a to a predetermined speed ratio or torque ratio to rotate thepulsator.

A dehydration shaft 9 is connected to the washing tub 4 and has a pipeshape including a first hollow 9 h (refer to FIG. 5) through which thedrive shaft 6 a passes. A hub base 18 which is coupled to a bottom ofthe washing tub 4 may be provided below the washing tub 4. Thedehydration shaft 9 may be coupled to the hub base 18.

A bearing housing 16 may be disposed on a lower side of the reservoir 1.The bearing housing 16 may be coupled to a bottom surface of thereservoir 1. A bearing 19 for supporting the dehydration shaft 9 may beprovided in the bearing housing 16.

The bearing housing 16 is coupled to the bottom surface of the reservoir3 by a fastening member such as a screw or bolt, and a space in whichthe bearing 19 is accommodated is formed between the bottom surface ofthe reservoir and the bearing housing 16. An opening portion throughwhich the dehydration shaft 9 passes is formed in a bottom of thebearing housing 16.

The motor 6 may be an outer rotor type brushless direct current (BLDC)motor. However, the type of the motor 6 is not limited to this. Forexample, the motor 6 may be an inner rotor type motor, an AC motor suchas an induction motor or a shaded pole motor, or various other knowntype motors.

The motor 6 may include a stator 61 in which a stator coil 61 b is woundaround a stator core 61 a and a rotor frame 63 to which a plurality ofpermanent magnets circumferentially spaced from the stator 61 is fixed.A rotor hub 65 for connecting a center portion of the rotor frame 63 tothe drive shaft 6 a may be further provided. The rotor frame 63 isrotated by an electromagnetic force between the plurality of permanentmagnets 62 and the stator 61, and thus, the drive shaft 6 a is alsorotated.

Meanwhile, referring to FIGS. 4A and 4B, the rotor hub 65 may include arotor bush 65 a which is coupled to the drive shaft 6 a and a couplingflange 65 b which couples the rotor bush 65 a to the center portion ofthe rotor frame 63. The coupling flange 65 b may include a tubularflange body portion 65 b 1 into which the rotor bush 65 a is inserted,and a flange portion 65 b 2 which extends outward from the flange bodyportion 65 b 1 and is coupled to the rotor frame 63 by a fasteningmember such as a bolt or bolt. In particular, engagement grooves 65 b 3which mesh with the clutching coupler 41 along the circumferentialdirection may be formed on an inner peripheral surface of the flangebody portion 65 b 1.

A clutch 40 for shaft-coupling (or, connecting) or a shaft-decoupling(or, disconnecting) the drive shaft 6 a and the dehydration shaft 9 isprovided. The clutch 40 is provided to be lifted or lowered along thedehydration shaft 9 below the solenoid 50. The clutch 40 shaft-couplesthe drive shaft 6 and the dehydration shaft 9 at a connection position,and shaft-decouples the drive shaft 6 and the dehydration shaft 9 at adisconnection position lifted from the connection position by a suctionforce of the solenoid 50.

The clutch 40 is disposed below the solenoid 50 as a whole. However, anarmature 42 (or a plunger) which forms a magnetic path of a flux formedby the solenoid 50 or a movable core may partially reach the inside ofsolenoid 50. The armature 42 may be made of ferromagnetic material. Whena current is applied to the solenoid 50, the armature 42 is lifted by anattraction force between a magnetic core 16 a and the armature 42.

Referring FIGS. 3A to 3C and FIGS. 5A and 5B, the clutch 40 may furtherinclude the clutching coupler 41. The clutching coupler 41 is formed ina cylindrical shape as a whole and includes a second hole 41 h intowhich the dehydration shaft 9 is inserted. The clutching coupler 41 maybe made of a synthetic resin material, but is not necessarily limitedthereto, and may be made of a metal (for example, ferromagneticmaterial).

In the clutching coupler 41, an inner circumferential surface definingthe second hollow 41 h is spline-coupled to an outer circumferentialsurface of the dehydration shaft 9, and thus, the clutching coupler 41may move in an axial direction (longitudinal direction of thedehydration shaft 9) in a state where a rotation of the clutch 40 withrespect to the dehydration shaft 9 is restricted. The innercircumferential surface may include engagement grooves 41 r which meshwith (or engage with) teeth 9 a (refer to FIG. 2) formed on the outercircumferential surface of the dehydration shaft 9.

The clutching coupler 41 shaft-couples (connects) the drive shaft 6 aand the dehydration shaft 9 to each other at a lowered positioncorresponding to the connection position (refer to FIG. 5A) of theclutch 40, and shaft-decouples the drive shaft 6 a and the dehydrationshaft 9 at a lifted position corresponding to the disconnection position(refer to FIG. 5B) of the clutch 40.

Teeth 41 a, which mesh with the engagement grooves 65 b 3 of thecoupling flange 65 b when the clutching coupler 41 is located at thelowered position, are formed a lower end of the clutching coupler 41.

Lifting or lowering operation of the clutch coupler 41 performed alongthe dehydration shaft 9 is realized by the armature 42. That is, theclutching coupler 41 is lifted by a lifting force generated from thearmature 42 which is lifted by an electromagnetic interaction with thesolenoid 50.

The clutching coupler 41 is coupled to the armature 42 and can be liftedintegrally with the armature 42. The clutching coupler 41 and thearmature 42 can be integrally formed by injecting a synthetic resin withthe rotor armature 42 inserted into a mold to form the clutching coupler41.

Referring to FIGS. 5A and 5B, an elastic member 39 which pushes theclutch 40 downward may be further provided. The lifting force acting onthe clutch 40 by a magnetic field of the solenoid 50 is larger than alowering force applied from the elastic member 39 to the clutch 40 sothat the clutch 40 can be lifted when a current is applied to thesolenoid 50.

The elastic member 39 may be a coil spring. The coil spring 39 may bedisposed inside a bobbin 51 and may be interposed between the bearing 35and the clutching coupler 41. An upper end of the coil spring 39 may bein contact with the bearing 35 and a lower end thereof may be in contactwith the clutching coupler 41.

A magnetic core 16 a surround a periphery of the solenoid 50 isprovided. The magnetic core 16 a forms a magnetic path through which themagnetic field generated by the solenoid 50 passes. The magnetic core 16a may be formed in the bearing housing 16.

Referring to FIGS. 3A to 3C, the armature 42 may include a core base 421which is disposed below the magnetic core 16 a and extends outward fromthe clutching coupler 41 and a core outer portion 442 which extendsupward from an outer periphery of the core base 421. An upper end of thecore outer portion 442 may be disposed radially outside the magneticcore 16 a.

A lever 80 is provided in the dehydration shaft 9. The lever 80 has asupport point SP of which a position is fixed with respect to thedehydration shaft 9 and an operating end E1 which is located at a pointspaced by a predetermined distance from the support point SP.

The lever 80 may be formed by bending a metal wire (for example,stainless steel). A tubular insertion hole 41 b extending in ahorizontal direction is formed in the dehydration shaft 9, and one endof the lever 80 is inserted into the insertion hole 41 b.

The lever 80 may include a vertical portion 81 which extends vertically,a support portion 82 which is bent at an upper end of the verticalportion 81 and horizontally extends in a first direction, and anoperating portion 83 which horizontally extends in a second directionopposite to the first direction at a lower end of the vertical portion81.

The support portion 82 may be inserted into the insertion hole 41 b andthe operating end E1 is provided on one end of the operating portion 83.The support point SP may be a point corresponding to an inlet of theinsertion hole 41 b on the support portion 82. The elastic member 39 maybe disposed below the support portion 82.

A guide groove 90 may be provided on an inner peripheral surface of theclutching coupler 41 defining the second hole 41 h. In the embodiment,the guide groove 90 is formed on the inner peripheral surface of theclutch coupler 41. However, the present invention is not limited tothis. The guide groove 90 may be formed on a member separated from theclutching coupler 41 and the member may be coupled to the innerperipheral surface of the clutching coupler 41.

The guide groove 90 guides a relative movement of the operating end E1with respect to the clutching coupler 41 when the clutching coupler 41is lifted or lowered. The operating end E1 is located in the guidegroove 90, and a position of the operating end E1 in the guide groove 90is changed according to the lifting or lowering operation of theclutching coupler 41.

A lowering restriction section 110 may be disposed inside the guidegroove 90. When the clutching coupler 41 is located at the liftedposition, the operating end E1 is caught by the lowering restrictionsection 110. Accordingly, the clutching coupler 41 is not lowered andmaintained at the lifted position.

That is, when the clutching coupler 41 is located at the liftedposition, the clutching coupler 41 tries to move downward by not only aself-weight of the clutching coupler 41 but also a restoring force ofthe compressed elastic member 39. However, the operating end E1 iscaught by the lowering restriction section 110, and thus, the clutchingcoupler 41 cannot be further lowered. Accordingly, even when a currentis not applied to the solenoid 50, the lifted position of the clutchingcoupler 41 can be maintained.

The lowering restriction section 110 may protrude from a bottom of theguide groove 90. The lowering restriction section 110 may have a lockinggroove 112 which is formed to be open downward such that the operatingend E1 is inserted from below.

A predetermined point of the lever 80 between the support point SP andthe operating end E1 is pressed upward by an upper end of the elasticmember 39, and in this case, the operating end E1 presses a bottom 91 ofthe guide groove 90 by a moment M generated based on the support pointSP. Accordingly, the operating end E1 is prevented from separated fromthe guide groove 90.

The upper end of the elastic member 39 can press the support portion 82.A point at which the support portion 82 is pressed by the elastic member39 is a point spaced by a predetermined distance from the support pointSP.

Meanwhile, a separation guide section 120 is provided in the guidegroove 90. The separation guide section 120 may protrude from the bottom91 of the guide groove 90. When the clutching coupler 41 is lifted, theseparation guide section 120 guides the operating end E1 so that theoperating end E1 turns about the support point EP. The operating end E1is separated from the locking groove 112 while being turned by theseparation guide section 120.

The guide section 90 may include a lifting guide section S1 which guidesthe operating end E1 guided by the separation guide section 120 when theclutching coupler 41 is lowered. When the current applied to thesolenoid 50 is cut off and the clutching coupler 41 is lowered, theoperating end E1 is guided by the lifting guide section S1 and reachesan operating end lifted point P1 located above the lowering restrictionsection 110. In a state where the operating end E1 is located at theoperating end lifted point P1, the clutching coupler 41 is maintained atthe lower position by the restoring force acting downward from theelastic member 39.

The guide groove 90 may include a lowering guide section S2 which guidesthe operating end E1 from the operating end lifted point P1 to a secondpoint P2 located below the locking groove 112 when the clutching coupler41 is lifted. When the current is applied to the solenoid 50 and theclutching coupler 41 is lifted, the operating end E1 is guided along thelowering guide section S2 and reaches the second point P2.

The guide groove 90 may include a guide section S3 which guides theoperating end E1 from the second point P2 to the locking groove 112 whenthe clutching coupler 41 is lifted. When the current is applied to thesolenoid 50 and the clutching coupler 41 is lifted, the operating end E1at the lowering guide section S2 is guided along the guide section S3and reaches the locking groove 112.

Hereinafter, an operation of a clutch system will be described withreference to FIGS. 7 to 8B.

When the clutch 40 is located at the disconnection position (or, liftedposition), a current is not applied to the solenoid 50, and theoperating end E1 is located in the locking groove 112 of the loweringrestriction section 110. A position at this time is indicated by P0 inFIG. 7. In this state, the dehydration shaft 9 is separated(disconnected) from the drive shaft 6 a, and only the pulsator 5 isrotated by the drive shaft 6 a.

The guide groove 90 includes a lowering guide section S0 which guidesthe operating end E1 located in the locking groove 112 to an operatingend lowered point Pa2 located below the locking groove 112 when theclutching coupler 41 is lifted.

If a current is applied to the solenoid 50, the clutching coupler 41 islifted, the operating end E1 interferes with an upper surface of theseparation guide section 120, is guided downward along an inclination ofthe upper surface from the position Pa1, and reaches the operating endlowered point Pa2. Here, the operating end E1 is moved only within arange in which the lever 80 can be turned based on the support portion82, in actual, the clutching coupler 41 which is a counterpart is moved,and thus, the “movement” of the operating end E1 mainly is a relativemovement with respect to the clutching coupler 41, which is similarlyapplied to the following.

The bottom 91 of the guide groove 90 is inclined to gradually descendfrom the position Pa1 to the operating end lowered point Pa2 and isstepped so that a height of the bottom 91 discontinuously decreases at aboundary B1. The operating end lowered point Pa2 is a point where theoperating end E1 reaches after the step.

If the supply of the current to the solenoid 50 is cut off in a statewhere the operating end E1 reaches the operating end lowered point Pa2,the clutching coupler 41 is lowered by the restoring force of theelastic member 39, and the operating end E1 moves along the liftingguide section S1. Meanwhile, if the current is not continuously appliedto the solenoid 50 in a process in which the operating end E1 is liftedalong the lifting guide section S1, the clutching coupler 41 isaccelerated according to the lowering of the clutching coupler 41 andhas an excessive speed when the clutching coupler 41 collides with therotor hub 65 (refer to a graph indicated by the “related art” in FIG.8B). Accordingly, an impact noise is generated, and in some cases,components may be damaged.

Accordingly, the controller 17 may repeat application and interruptionof the current to the solenoid 50 before the operating end E1 reachesthe operating lifted point such that the clutching coupler 41 isdecelerated while being lowered. While the current is applied to thesolenoid 50, a lowering speed of the clutching coupler 41 is reduced byan attraction between the magnetic core 16 a and the armature 42.

After the controller 17 applies the current to the solenoid 50 for afirst time Δt1, the control unit 17 cuts off the current for a secondtime 42, and thereafter, applies the current again for a third time 43.Preferably, the third time Δt3 is shorter than the first time Δt1.

Here, the current is applied for the time Δt1 in order to prevent theclutching coupler 41 from being rapidly accelerated by the restoringforce of the elastic member 39 at the beginning of the lowering of theclutching coupler 41, and it is preferable that the first time Δt1 isset to be longer than the third time Δt3 in order to achieve sufficientbraking.

Meanwhile, after the controller 17 repeatedly cuts off the current forthe second time Δt2 and applies the current for the third time Δt3, thecontroller 17 may cut off the current for a fourth time Δt4, andthereafter, may apply the current again for a fifth time Δt5. Here, thefifth time Δt5 may be shorter than the first time Δt1. While the currentis applied for the fifth time Δt5, preferably, the operating end E1reaches the operating end lifted point P1.

Meanwhile, the lifting guide section S1 extends upward from theoperating end lowered point Pa2 to the operating end lifted point P1,the bottom 91 of the guide groove 90 in the lifting guide section S1 isinclined so that the height of the bottom 91 gradually increases fromthe operating end lowered point Pa2 toward the operating end liftedpoint P1 side and is stepped so that the height of the bottom 91discontinuously decreases at a boundary B2. The operating end liftedpoint P1 is a point where the operating end E1 reaches after theboundary B2.

If a current is applied to the solenoid 50 in a state where theoperating end E1 reaches the operating end lifted point P1, theclutching coupler 41 is lifted again, the operating end E1 comes intocontact with a lowering guide surface 111 formed on the upper surface ofthe lowering restriction section 110 and moves downward along aninclination of the lowering guide surface 111. The operating end E1moves downward along the lowering guide section S2 of the guide groove90 and reaches the second point P2.

The lowering guide section S2 extends downward from the operating endlifted point P1 to the position Pb side, the bottom 91 of the guidegroove 90 in the lowering guide section S2 is inclined so that theheight of the bottom 91 gradually increases from the P1 toward theposition Pb side and is stepped so that the height of the bottom 91discontinuously decreases at a boundary B3. The second point P2 is apoint where the operating end E1 reaches after the boundary B3.

If the supply of the current to the solenoid 50 is cut off in a statewhere the operating end E1 reaches the second point P2, the clutchingcoupler 41 is lowered by the restoring force of the elastic member 39,and the operating end E1 moves along the guide section S3 to enter thelocking groove 91. More specifically, if the clutching coupler 41 islowered in a state where the operating end E1 is located at the secondpoint P2, the operating end E1 comes into contact with the lower surfaceof the lowering restriction section 110 at the position Pb, is guidedalong an upward inclination surface 112 formed on the lower surface, andenter the locking groove 91.

The guide section S3 extends upward from the position Pb to the positionP0 side, the bottom 91 of the guide groove 90 in the guide section S3 isinclined so that the height of the bottom 91 gradually decreases fromthe Pb toward the position P0 side and is stepped so that the height ofthe bottom 91 discontinuously decreases at a boundary B4. The positionP0 is a point where the operating end E1 reaches after the boundary B4.

Hereinbefore, preferred embodiments of present disclosure areillustrated and described. However, present disclosure is not limited tothe specific embodiments described above, the present disclosure may bevariously modified by those skilled in the art without departing from ascope of the present disclosure claimed in the claims, and themodifications should not be understood individually from a technicalspirit or outlook of the present disclosure.

In the washing machine of the present disclosure, the connection or thedisconnection between the drive shaft and the dehydration shaft can bemaintained even when a current is not applied to the solenoid.Accordingly, it is possible to reduce power consumption.

In addition, a current is intermittently supplied to the solenoid whilethe clutching coupler is lowered, and thus, the lowering speed of thearmature decreases. Accordingly, the speed of the clutching couplermoving integrally with the armature can be reduced, the impact noisebetween the clutching coupler and the rotor hub can be reduced, anddamages caused by impacts can be reduced.

Moreover, in the washing machine of the present disclosure, a closecontact between the operating end of the lever and the bottom of theguide groove is maintained, and thus, it is possible to prevent theoperating end from being separated from the guide groove.

In addition, the bottom of the guide groove and the operating end comeinto close contact with each other, and thus, the lever can be correctlydeformed according to the height of the bottom.

Moreover, in the washing machine of the present disclosure, a separatemotor used to operate the clutch system and all components associatedwith the motor in the related art are removed. Accordingly, amanufacturing cost of a product can be reduced.

Furthermore, air between the clutching coupler and the dehydration shaftis discharged through the guide grooves formed on the inner peripheralsurface of the clutching coupler while the clutching coupler is lifted,and thus, damping effects can be obtained.

What is claimed is:
 1. A washing machine comprising: a washing tubaccommodating laundry and rotatably disposed; a pulsator rotatablydisposed in the washing tub; a drive shaft rotating the pulsator; adehydration shaft connected to the washing tub and having a first hollowthrough which the drive shaft passes; a solenoid generating a magneticfield when a current is applied; a controller configured to control thecurrent applied to the solenoid; a magnetic core surrounding a peripheryof the solenoid; an armature lifted by an attraction force between thearmature and the magnetic core when a current is applied to thesolenoid; a clutching coupler having a second hole through which thedehydration shaft passes, wherein the clutching coupler is lifted andlowered along the dehydration shaft integrally with the armature,shaft-couples the drive shaft and the dehydration shaft to each other ata lowered position, and shaft-decouples the drive shaft and thedehydration shaft from each other at a lifted position lifted from thelowered position according to the lifting of the armature; a leverhaving a support point of which a position is fixed with respect to thedehydration shaft and an operation end located at a point spaced by apredetermined distance from the support point; an elastic memberpressing the clutching coupler downward; a guide groove provided on aninner peripheral surface of the clutching coupler defining the secondhole and guiding a relative movement of the operating end with respectto the clutching coupler when the clutching coupler is lifted orlowered; and a lowering restriction section disposed in the guide grooveand having a locking groove caught by the operating end so that theclutching coupler is not lowered in a state where the clutching coupleris located at the lifted position and a current is not applied to thesolenoid, wherein the guide groove includes a lowering guide sectionwhich guides the operating end located in the locking groove to anoperating end lowered point located below the locking groove when theclutching coupler is lifted and a lifting guide section which guides theoperating end located at the operating end lowered point to an operatingend lifted point located above the lowering restriction section when theclutching coupler is lowered, and the controller cuts off the currentapplied to the solenoid in a state where the operating end is located atthe operating end lowered point so that the operating end is guidedalong the lifting guide section and repeats application and interruptionof the current to the solenoid until the operating end reaches theoperating end lifted point.
 2. The washing machine of claim 1, whereinafter the controller applies the current to the solenoid for a firsttime, the controller cuts off the current for a second time, andthereafter, applies the current again for a third time shorter than thefirst time.
 3. The washing machine of claim 2, wherein after thecontroller repeatedly cuts off the current for the second time andapplies the current for the third time, the controller cuts off thecurrent for a fourth time, and thereafter, applies the current for afifth time longer than the third time.
 4. The washing machine of claim3, wherein the fifth time is shorter than the first time.
 5. The washingmachine of claim 1, wherein the lowering restriction section includes alocking groove configured to be formed to be open downward such that theoperating end is inserted from below, and the washing machine furthercomprising: a separation guide section configured to be located in theguide groove, to come into contact with the operating end when thecurrent is applied to the solenoid in a state where the operating end islocated in the locking groove, and to guide turning of the operating endabout the support point such that the operating end is separated fromthe locking groove.